Retrieving shapefile point color from .SHP file?

1

I have been fighting with shapefiles for a little over a week now and I am guessing that I am missing a very crucial feature. When I add a shapefile, I can draw it by manually adjusting the fillcolor, pointsize, filltransparency, etc… but what about retrieving that information from the shapefile itself? If i Make a shapefile in ArcGIS or qGIS, and I set those attributes before I save it, shouldn’t MapWinGIS be able to retrieve that data without having to set it?

I just need somebody to point me in the right direction here. I am coding in VB.net.

2

I also want to add that I have seen many posts on this forum that dont quite ask this quesiton. this post "
Where can I get shapefile data " got me to the two examples listed within, but the point options are set within the code, not retrieved from the shapefile.

So two questions. Can we retrieve point/polygon drawing options FROM the shapefile? or must we set them AFTER the shapefile is loaded?

thanks again.

3

Hi,

The “symbology” information (how a shapefile is drawn) is not stored in the shapefile.
In the case of ArcGIS (ArcMap) it is stored in the map document (.mxd).
A shapefile only contains the data for the layer like: Geometry and Attributes att a minimum.
And a shapefile is not a single file but a collection of files where only the file extension differ.

Here you can read all about how and what is stored in ha shapefile

Regards
Daniel

4

Thank you so much for your reply. So it sounds like the best thing I can do is allow the user to import the Shapefile, and then manually adjust the layer settings. That’s cumbersome but workable. I already have a basic UI that lets the user adjust basic layer characteristics while the application is running, it just seems slow and repetitive unless I come up with a way to save a layer settings memory file of some sort.

The ESRI document you pointed me to was extremely interesting. Thanks for that as well.

Regards,
Eric

5

I have some C# simple code:
Shpfile = open.FileName;
bool openResult = sf.Open(Shpfile, null);
float temp = sf.DefaultDrawingOptions.LineWidth;
uint lincolor = sf.DefaultDrawingOptions.LineColor;
other attributes are similar.
I hope it is useful.